49th Annual Meeting of the Division of Plasma Physics
Volume 52, Number 11
Monday–Friday, November 12–16, 2007;
Orlando, Florida
Session GI1: Direct Drive Inertial Confinement Fusion and Z Pinches
9:30 AM–12:30 PM,
Tuesday, November 13, 2007
Rosen Centre Hotel
Room: Junior Ballroom
Chair: Craig Sangster, University of Rochester, Laboratory for Laser Energetics
Abstract ID: BAPS.2007.DPP.GI1.1
Abstract: GI1.00001 : Performance of Direct-Drive Cryogenic Targets on OMEGA
9:30 AM–10:00 AM
Preview Abstract
Abstract
Author:
V.N. Goncharov
(Laboratory for Laser Energetics, U. of Rochester)
Cryogenic D$_{2}$ and DT targets are routinely imploded on the
OMEGA Laser
System to study ignition-relevant, high-convergence-ratio,
direct-drive
physics. High-performance target designs depend crucially on the
accuracy of
the physics models used to simulate the implosions. To validate the
predictive capabilities of the physics models, computer
simulations have
been benchmarked against a variety of precision measurements,
including
laser-energy absorption, x-ray emission spectra, neutron and
charged-particle yields and spectra, core emission spectra, and
time-resolved hard-x-ray spectra ($>$20 keV). The target designs are
characterized by the shell adiabat \textit{$\alpha $} (ratio of
the fuel pressure to the
Fermi-degenerate pressure) and the peak drive intensity. Targets
for the
OMEGA experiments included both ``ice--CD'' designs, consisting
of a 65- to
100-\textit{$\mu $}m ice layer with a 3- to 13-\textit{$\mu $}m
CD overcoat, and 40- to 70-\textit{$\mu $}m wetted-foam
designs with a 2- to 5-\textit{$\mu $}m CH overcoat. The
cryogenic shells were driven using
high-contrast-ratio (up to 100) pulse shapes, including picket
pulses to
shape the adiabat inside the shell to improve stability. This
talk will
review the results of OMEGA cryogenic implosions with shell
adiabats in the
range 1 $<$ \textit{$\alpha $} $<$ 10 and peak intensities
varying from 2 $\times $ 10$^{14}$
to 1.5 $\times $ 10$^{15}$ W/cm$^{2}$. High-areal-density,
cryogenic fuel
assembly (\textit{$\rho $R} $>$ 0.2 g/cm$^{2}$,$^{
}$\textit{$\rho $}$_{D2} \quad \sim $ 100 g/cm$^{3}$, 500
$\times $ LD) is achieved when the excessive hot-electron and
radiation
preheat is mitigated. The experimental database of cryogenic targets
imploded on the OMEGA laser will be used to design
direct-drive-ignition
targets for the National Ignition Facility. This work was
supported by the
U.S. Department of Energy Office of Inertial Confinement Fusion
under
Cooperative Agreement DE-FC52-92SF19460.
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Contributors: R.S. Craxton, J.A.
Delettrez, D.H. Edgell, R. Epstein, V. Yu. Glebov, D.R. Harding,
S.X. Hu,
I.V. Igumenshchev, R. Janezic, R.L. Keck, J.P. Knauer, S.J.
Loucks, L.D.
Lund, J.R. Marciante, J.A. Marozas, F.J. Marshall, D.N. Maywar, R.L.
McCrory, P.W. McKenty, D.D. Meyerhofer, P.B. Radha, S.P. Regan,
R.G. Roides,
T.C. Sangster, W. Seka, V.A. Smalyuk, J.M. Soures, C. Stoeckl,
and S.
Skupsky, \textit{UR/LLE}; J.A. Frenje, C.K. Li, R.D. Petrasso,
\textit{MIT-PSFC}; D. Shvarts, \textit{NRCN (Israel)}.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.DPP.GI1.1